1H-NMR Metabolomic Study of the Mushroom Pleurotus djamor for the Identification of Nematocidal Compounds.

Due to the increasing populations of anthelmintic-resistant gastrointestinal nematodes and as a consequence of the adverse effects of synthetic drugs, this study focuses on the search for secondary metabolites with nematocidal activity from the edible mushroom Pleurotus djamor using The proton nuclear magnetic resonance (1H-NMR) metabolomics. The highest activity was shown by the ethyl acetate fractions of mycelium (EC50 290.8 µg/mL) and basidiomes (EC50 282.7 µg/mL). Principal component analysis (PCA) and hierarchical data analysis (HCA) of the 1H-NMR metabolic profiles data showed that the ethanolic extracts, the ethyl acetate, butanol, and water fractions from mycelium have different metabolic profiles than those from basidiomes, while low polarity (hexane) fractions from both stages of fungal development show similar profiles. Orthogonal partial least squares discriminant analysis (OPLS-DA) allowed the identification of signals in the 1H-NMR metabolic profile associated with nematocidal activity. The signals yielded via OPLS-DA and bidimensional NMR analysis allowed the identification of uracil as a component in the ethyl acetate fraction from basidiomes, with an EC50 of 237.7 µg/mL. The results obtained showed that chemometric analyses of the 1H-NMR metabolic profiles represent a viable strategy for the identification of bioactive compounds from samples with complex chemical profiles.

In Vitro Insecticidal Effect of Commercial Fatty Acids, ß-Sitosterol, and Rutin against the Sugarcane Aphid, Melanaphis sacchari Zehntner (Hemiptera: Aphididae).

ABSTRACT: The sugarcane aphid, Melanaphis sacchari Zehntner (Hemiptera: Aphididae), is the main pest of sorghum, Sorghum bicolor L. Moench (Poaceae), in Mexico. To control this insect, farmers currently use synthetic chemical insecticides, which are toxic to humans and biodiversity. However, natural products are a promising potential source of safer alternative means to control different agricultural pests. The main objective of this study was to evaluate the insecticidal effect of contact by fumigation of pure molecules of four commercial fatty acids (palmitic, stearic, pentadecanoic, and linoleic acids), the phytosterol ß-sitosterol, and the flavonoid rutin. The results showed that fatty acids were the most effective against M. sacchari; the highest mortality rate (85%) was produced by linoleic acid and the mean lethal concentration was 1,181 ppm, followed by stearic and palmitic acids with 74 and 63% mortality, respectively, at a concentration of 2,500 ppm at 72 h. The positive control, imidacloprid, had 100% mortality in 24 h and the Tween 20, negative control, exhibited 4% mortality in 72 h. Our results show that commercial fatty acids are effective against adults of M. sacchari and can be considered an environmentally friendly alternative to the frequent use of synthetic chemical insecticides.

Nematicidal Effect of Shiitake (Lentinula edodes) Extracts Against Haemonchus contortus.

During the previous decades, the indiscriminate use of anthelmintics for the control of gastrointestinal nematodes has generated anthelmintic resistance in different parts of the world. It is necessary to search for new sustainable control alternatives, such as the use of extracts from plants and edible mushrooms. Therefore, the aim of the present study was to evaluate the nematicidal activity of extracts and fractions of the edible mushroom Lentinula edodes against Haemonchus contortus eggs and infective larvae. The basidiomata of L. edodes ECS-401 were provided by the Tropical Fungi Laboratory of El Colegio de la Frontera Sur and were extracted with ethyl acetate, methanol, and water. Fractionation of the most active extract was carried out by open column chromatography. The bioassays were performed in 96-well microtiter plates using 100 eggs/larvae, a final volume of 100 µL, and different concentrations of extracts/fractions (n = 4). Bioassay readings were taken at 48 h for egg hatching inhibition (EHI) and at 24, 48 and 72 h for larval mortality (LM). The ethyl acetate extract exhibited the highest percentage of EHI (100%). For the LM bioassay, the aqueous extract was the most active (69%), but its fractions did not show larvicidal activity. The chemical profile of the aqueous extract was analyzed by high-performance liquid chromatography, which showed the presence of phenols, flavonoids, and terpenes. L. edodes extracts showed ovicidal and/or larvicidal activity.

In Vitro and In Vivo Nematicide Effect of Extract Fractions of Pleurotus djamor Against Haemonchus contortus.

Sheep haemonchosis is a disease that causes anemia, diarrhea, weight loss, low production, and even death of young animals. This represents a negative economic impact on the livestock sector. For decades, chemicals have been used to control this parasitic disease; however, cases of anthelmintic resistance have increased around the world. For this reason, the search for control alternatives is necessary. Several studies have shown that edible mushrooms of Pleurotus genus have different medicinal properties, including nematicidal activity. In this study, the chromatographic fractionation of the hydroalcoholic extract of fruiting bodies Pleurotus djamor was carried out to identify and isolate the metabolites responsible for nematicidal activity. From the fractionation of the extract, the fraction PdR2 and the subfraction PdB were obtained, which were evaluated against Haemonchus contortus under in vitro conditions. The nematicidal effect of the fraction PdB in gerbils infected artificially with H. contortus was evaluated. Finally, the analysis of the PdB fraction by gas chromatography-mass spectrometry and nuclear magnetic resonance was carried out. The results showed that the PdB had 100% of egg hatching inhibition from 5 mg/mL. Regarding larvicidal activity, it presented >97.2% from 24 h to 20 mg/mL. The in vivo evaluation of the PdB fraction showed a reduction of H. contortus larvae of 92.56%. The compounds present in this fraction were the mixture of allitol and an unidentified terpene in a ratio of 9:1. The PdB fraction is a potential alternative for the control of H. contortus, where allitol and a terpene could be responsible for nematicidal activity.

The Edible Mushroom Pleurotus djamor Produces Metabolites with Lethal Activity Against the Parasitic Nematode Haemonchus contortus.

Pleurotus djamor is an edible mushroom that has medicinal properties. This study aimed to assess the in vitro activity of P. djamor extracts and fractions against Haemonchus contortus eggs and exsheathed infective larvae (L3). Crude hydroalcoholic extracts were obtained by maceration and fractions were obtained through chromatography. Metabolite identity was determined using gas chromatography/mass spectrometry (GC-MS) analysis. The results showed that P. djamor extracts had no significant activity against eggs at the concentrations used. However, the extract showed 98.7% and 77% larval mortality 72 h postconfrontation at 320 and at 160 mg/mL, respectively. The chromatography analysis resulted in 23 fractions that were eventually grouped into three fractions (E1, E2, and E3). These fractions showed the following egg hatching inhibition percentages: E1 = 100, E2 = 38.7, and E3 = 5.5 at 10 mg/mL concentration 72 h postexposure. Likewise, larval mortality percentages after this period were 90.6, 100, and 0.44 at 40 mg/mL (P < .05), respectively. The GC-MS showed five major compounds in E1 fraction, including four fatty acids: (i) pentadecanoic, (ii) hexadecanoic, (iii) octadecadienoic, (iv) octadecanoic acid, and one terpene identified as ß-sitosterol. We concluded that the edible mushroom P. djamor possesses nematicidal metabolites, which could be used as an alternative anthelmintic treatment.